Telecommunication cabling systems, when implemented using electrical signals, utilize twisted pair wiring and electrical connectors to form communication channels between computing systems, routers, or other telecommunications and networking equipment. The wiring, formed as cables, as well as the electrical connectors, are required to meet electrical performance criteria set by such ISO standards.
For example, international standard ISO/IEC 11801 specifies general-purpose telecommunication cabling systems (structured cabling) that are suitable for a wide range of applications (analog and ISDN telephony, various data communication standards, building control systems, factory automation). The ISO/IEC standard covers both balanced copper cabling and optical cabling. The standard defines several classes, or categories, of twisted-pair copper interconnects, which differ in the maximum frequency for which a certain channel performance is required. For example, category 5c utilizes frequencies up to 100 MHz, while category 6 utilizes frequencies up to 250 MHz. Category 6a utilizes frequencies up to 500 MHz, and category 7 uses frequencies of up to 1 GHz.
When telecommunications equipment, including telecommunications connectors, are manufactured, they are therefore typically tested to ensure compliance with electrical performance characteristics. For example, when manufactured, the RF performance of RJ-45 modular jacks used in telecommunications networks is tested to determine compliance with such standards.
Due to the nature of RJ-45 modular plugs, there is a split pair (i.e., the “3-6 pair”) that has poor crosstalk performance. In order for the modular jack to achieve the requirements of category 5e and higher, such jacks require compensation to cancel some of the crosstalk of the modular plug. To achieve the requirements for category 6 and higher, the compensation within the jack has to be maintained within a very narrow performance band. This compensation is often contained in both the contact set of the modular jack as well as capacitive and inductive coupling on a circuit board. The majority of the compensation for the near-end crosstalk (NEXT) is capacitive and is usually included on a printed circuit board.
Due to the materials and manufacturing processes for inexpensive printed circuit boards, there is a significant amount of variability in the compensating capacitance between manufactured parts. These variations can shift the performance of an RJ-45 jack outside of the accepted performance range. In order to ensure quality product, production samples are often tested at the manufacturing site. These tests are time consuming and complicated to perform, requiring use of specialized test fixtures and a network analyzer. Furthermore, because such tests are performed after a finished product has been created, disassembly and fixing of any performance issues lead to inefficiencies. Finally, because of the difficulty involved in testing such RJ-45 jacks, performance testing is currently performed on a sampled basis, rather than testing every manufactured jack.